Optical film, manufacturing method thereof, and display device

ABSTRACT

An optical film includes a polarization film including a polymer resin and a dichroic dye, and a phase delay layer disposed on the polarization film and including a liquid crystal.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/751,482, filed on Jun. 26, 2015, which claims priorities to KoreanPatent Application Nos. 10-2014-0080188 and 10-2015-0088237 filed onJun. 27, 2014 and Jun. 22, 2015, and all the benefits accruing therefromunder 35 U.S.C. § 119, the content of which in its entirety is hereinincorporated by reference.

BACKGROUND 1. Field

The disclosure relates to an optical film, a manufacturing methodthereof, and a display device including the optical film.

2. Description of the Related Art

Commonly used flat panel displays may be classified into alight-emitting display device that emits light by itself and anon-emissive display device that includes a separate light source, andan optical or compensation film such as a retardation film is typicallyemployed for improving the image quality thereof.

In the case of the light emitting display device, for example, anorganic light emitting display, the visibility and the contrast ratiomay be deteriorated by reflection of external light caused by a metalsuch as an electrode. In the light emitting display device, the linearpolarized light is shifted into circularly polarized light using apolarizing plate and a retardation film to reduce such reflection ofexternal light, such that reflection of the external light by theorganic light emitting display and leakage thereof to the outside may beeffectively prevented.

In the liquid crystal display (“LCD”), which is the non-emissive displaydevice, the linear polarized light is changed into the circularlypolarized light to improve the image quality by reducing the externallight reflection, based on the type of device, such as transparent typeLCD, transflective type LCD, reflective type LCD, and so on.

However, a conventional optical film used in a flat panel displaytypically has weak optical durability and has an effect on displayquality, and has a thick thickness.

SUMMARY

An exemplary embodiment of the invention provides an optical film havingimproved optical durability and optical characteristics and a thinthickness.

Another exemplary embodiment provides a method of manufacturing theoptical film.

Yet another exemplary embodiment provides a display device including theoptical film.

According to an exemplary embodiment, an optical film includes apolarization film including a polymer resin and a dichroic dye, and aphase delay layer disposed on the polarization film and including aliquid crystal.

In an exemplary embodiment, in-plane phase retardation (R_(e0)) of thephase delay layer for 450 nanometers (nm), 550 nm and 650 nm wavelengthsmay satisfy the following inequality: R_(e0) (450 nm)≤R_(e0) (550nm)<R_(e0) (650 nm) or R_(e0) (450 nm)<R_(e0) (550 nm)≤R_(e0) (650 nm).

In an exemplary embodiment, the phase delay layer may have shortwavelength dispersion in a range from about 0.70 to about 0.99, and thephase delay layer may have long wavelength dispersion in a range fromabout 1.01 to about 1.20.

In an exemplary embodiment, in-plane phase retardation (R_(e0)) of thephase delay layer for 550 nm wavelength may be in a range from about 120nm to about 160 nm.

In an embodiment, the phase delay layer may include a first phase delaylayer and a second phase delay layer, the first and second phase delaylayers may have different retardation from each other, and each of thefirst and second phase delay layers may include liquid crystal.

In an exemplary embodiment, the first phase delay layer may be a λ/2phase delay layer, and the second phase delay layer may be a λ/4 phasedelay layer.

In an exemplary embodiment, the first phase delay layer and the secondphase delay layer may each have a refractive index satisfying thefollowing relationship: n_(x)>n_(y)=n_(z) or n_(x)<n_(y)=n_(z), wheren_(x) denotes a refractive index of the first or second phase delaylayer at a slow axis thereof, n_(y) denotes a refractive index of thefirst or second phase delay layer at a fast axis thereof, and n_(z)denotes a refractive index of the first or second phase delay layer in adirection perpendicular to the slow and fast axes thereof.

In an exemplary embodiment, in-plane phase retardation (R_(e1)) of thefirst phase delay layer for 450 nm, 550 nm and 650 nm wavelengths maysatisfy the following inequality: R_(e1) (450 nm)>R_(e1) (550 nm)>R_(e1)(650 nm), in-plane phase retardation (R_(e2)) of the second phase delaylayer for 450 nm, 550 nm and 650 nm wavelengths may satisfy thefollowing inequality: R_(e2) (450 nm)>R_(e2) (550 nm)>R_(e2) (650 nm),and entire in-plane phase retardation (R_(e0)) of the first phase delaylayer and the second phase delay layer for 450 nm, 550 nm and 650 nmwavelengths may satisfy the following inequality: R_(e0) (450 nm)≤R_(e0)(550 nm)<R_(e0) (650 nm) or R_(e0) (450 nm)<R_(e0) (550 nm)≤R_(e0) (650nm).

In an exemplary embodiment, the first phase delay layer and the secondphase delay layer may each have short wavelength dispersion in a rangefrom about 1.1 to about 1.2, and the first phase delay layer and thesecond phase delay layer may have entire short wavelength dispersion ina range from about 0.70 to about 0.99.

In an exemplary embodiment, the first phase delay layer and the secondphase delay layer may each have long wavelength dispersion in a rangefrom about 0.9 to about 1.0, and the first phase delay layer and thesecond phase delay layer may have entire long wavelength dispersion in arange from about 1.01 to about 1.20.

In an exemplary embodiment, in-plane phase retardation (R_(e1)) of thefirst phase delay layer for 550 nm wavelength may be in a range fromabout 230 nm to about 270 nm, in-plane phase retardation (R_(e2)) of thesecond phase delay layer for 550 nm wavelength may be in a range fromabout 100 nm to about 140 nm, and entire in-plane phase retardation(R_(e0)) of the first phase delay layer and the second phase delay layerfor 550 nm wavelength may be in a range from about 120 nm to about 160nm.

In an embodiment, an angle between a slow axis of the first phase delaylayer and a slow axis of the second phase delay layer may be in a rangefrom about 50 degrees to about 70 degrees.

In an exemplary embodiment, the optical film may further include anadhesion layer disposed between the first phase delay layer and thesecond phase delay layer.

In an exemplary embodiment, the phase delay layer may have a thicknessless than or equal to about 10 micrometers (μm).

In an exemplary embodiment, the optical film may further include anadhesion layer disposed between the polarization film and the phasedelay layer.

In an exemplary embodiment, the polymer resin may include a polyolefin,a polyamide, a polyester, a polyacryl, polystyrene, a copolymer thereof,or a combination thereof.

In an exemplary embodiment, the polymer resin may include polyethylene(PE), polypropylene (PP), polyethylene terephthalate (PET), polyethyleneterephthalate glycol (PETG), polyethylene naphthalate (PEN), nylon, acopolymer thereof, or a combination thereof.

In an exemplary embodiment, the polarization film may have a thicknessless than or equal to about 100 μm.

In an exemplary embodiment, the polarization film may include a meltblend of the polymer resin and the dichroic dye.

In an exemplary embodiment, a transparent substrate may not be presentbetween the polarization film and the phase delay layer.

According to another exemplary embodiment, a display device including anoptical film described above.

According to another exemplary embodiment, a method of manufacturing anoptical film includes melt-blending a polymer resin and a dichroic dyeto prepare a polarization film, preparing a phase delay layer includingliquid crystal on a substrate, and providing the phase delay layer onthe polarization film.

In an exemplary embodiment, the providing the phase delay layer on thepolarization film may include removing the phase delay layer from thesubstrate and transferring it to a surface of the polarization film.

In an exemplary embodiment, the manufacturing method may further includeproviding an adhesion layer on a surface of the polarization film.

In an exemplary embodiment, the preparing the phase delay layer mayinclude stacking a λ/2 phase delay layer and a λ/4 phase delay layer onthe substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the invention will become more apparentby describing in further detail exemplary embodiments thereof withreference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of an exemplary embodiment ofan optical film according to the invention;

FIG. 2 is a schematic view showing the external light anti-reflectionprinciple of an exemplary embodiment of an optical film according to theinvention;

FIG. 3 is a schematic view of an exemplary embodiment of a polarizationfilm according to the invention;

FIG. 4 is a schematic view of an alternative exemplary embodiment of anoptical film according to the invention;

FIG. 5 is a schematic cross-sectional view of an exemplary embodiment ofan organic light emitting display according to the invention; and

FIG. 6 is a schematic cross-sectional view of a liquid crystal display(“LCD”) device according to the invention.

DETAILED DESCRIPTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Hereinafter, an exemplary embodiment of an optical film according to theinvention will be described referring to FIG. 1.

FIG. 1 is a schematic cross-sectional view of an exemplary embodiment ofan optical film according to the invention, FIG. 2 is a schematic viewshowing the external light anti-reflection principle of an exemplaryembodiment of an optical film according to the invention, and FIG. 3 isa schematic view of an exemplary embodiment of a polarization filmaccording to the invention.

Referring to FIG. 1, an exemplary embodiment of an optical film 100according to the invention includes a polarization film 110 and a phasedelay layer 120 disposed on the polarization film 110. In one exemplaryembodiment, for example, the phase delay layer 120 may be disposed orstacked on a surface of the polarization film 110. The phase delay layer120 may be, for example, a λ/4 plate, and the phase delay layer 120 maycircularly polarize light passing through the polarization film 110 andthus cause retardation and have an influence on absorption andreflection of the light.

Such an embodiment of the optical film 100 may be disposed on a surfaceor both surfaces of a display device. In one exemplary embodiment, forexample, the optical film 100 may be disposed on a screen side of thedisplay device, and thus may effectively prevent reflection of lightflowing in from the outside (hereinafter referred to as “reflection ofexternal light”). Therefore, the optical film 100 may effectivelyprevent visibility deterioration due to the reflection of externallight.

FIG. 2 is a schematic view showing the external light anti-reflectionprinciple of an exemplary embodiment of an optical film according to theinvention.

Referring to FIG. 2, when incident unpolarized light from the outside ispassed through the polarization film 110, and the polarized light isshifted into circularly polarized light by passing through the phasedelay layer 120, only a first polarized component (e.g., a horizontalcomponent), which is one of two polarized components perpendicular toeach other, is transmitted. When the circularly polarized light isreflected in a display panel 50 including a substrate, an electrode andso on, the circularly polarized light changes the circular polarizationdirection, and the circularly polarized light passes through the phasedelay layer 120 again, such that only a second polarized component(e.g., a perpendicular component), which is the other of the twopolarized components, may be transmitted. As the second polarizedperpendicular component is not passed through the polarization film 110,and light does not exit to the outside, thereby effectively preventingthe external light reflection.

Referring to FIG. 3, the polarization film 110 has a self-integratedstructure including a polymer resin 71 and a dichroic dye 72, e.g., madeof a melt blend of the polymer resin 71 and the dichroic dye 72.

In an exemplary embodiment, the polymer resin 71 may include, forexample, a hydrophobic polymer resin, for example a polyolefin resinsuch as polyethylene (“PE”), polypropylene (“PP”), and a copolymerthereof; a polyamide resin such as nylon and an aromatic polyamide; apolyester resin such as polyethylene terephthalate (“PET”), polyethyleneterephthalate glycol (“PETG”), and polyethylene naphthalate (“PEN”); apolyacrylic resin such as polymethyl(meth)acrylate; a polystyrene resinsuch as polystyrene (“PS”) and an acrylonitrile-styrene copolymer; apolycarbonate resin; a vinyl chloride-based resin; a polyimide resin; asulfone resin; a polyethersulfone resin; a polyether-etherketone resin;a polyphenylene sulfide resin; a vinyl alcohol resin; a vinylidenechloride resin; a vinyl butyral resin; an allylate resin; apolyoxymethylene resin; an epoxy resin; a copolymer thereof; or acombination thereof.

In one exemplary embodiment, the polymer resin 71 may include, forexample, a polyolefin resin, a polyamide resin, a polyester resin, apolyacrylic resin, a polystyrene resin, a copolymer thereof, or acombination thereof, and for another example, PE, PP, PET, PETG, PEN,nylon, a copolymer thereof, or a combination thereof.

In one exemplary embodiment, the polymer resin 71 may include, forexample, at least two of PE, PP, and a copolymer of polyethylene andpolypropylene (“PE-PP”). In an alternative exemplary embodiment, thepolymer resin 71 may include a mixture of PP and a PE-PP.

The PP may have, for example, a melt flow index (“MFI”) in a range fromabout 0.1 gram per 10 minutes (g/10 min) to about 5 g/10 min. Herein,the MFI is defined as the amount of a polymer in a melt state flowingper 10 minutes, and relates to viscosity of the polymer in a meltedstate. Accordingly, as the MFI is lower, the polymer has higherviscosity, while as the MFI is higher, the polymer has lower viscosity.When the PP has a MFI within the range, properties of a final productand workability may be effectively improved. In one exemplaryembodiment, for example, the polypropylene may have a MFI in a rangefrom about 0.5 g/10 min to about 5 g/10 min.

In an exemplary embodiment, the PE-PP may include an ethylene group inan amount in a range from about 1 weight percent (wt %) to about 50 wt %based on the total amount of the copolymer. When the PE-PP includes theethylene group in an amount within the range, phase separation of thepolypropylene and the PE-PP may be effectively prevented or suppressed.In such an embodiment, the PE-PP may improve an elongation rate duringelongation as well as have high light transmittance and alignment,thereby improving polarization characteristics. In one exemplaryembodiment, for example, the PE-PP may include an ethylene group in anamount in a range from about 1 wt % to about 25 wt % based on the totalamount of the copolymer.

The PE-PP may have a MFI in a range from about 5 g/10 min to about 15g/10 min. When the PE-PP has a MFI within the range, properties of afinal product as well as workability may be effectively improved. In oneexemplary embodiment, for example, the PE-PP may have a MFI in a rangefrom about 10 g/10 min to about 15 g/10 min.

The polymer resin 71 may include the PP and the PE-PP in a weight ratioin a range from about 1:9 to about 9:1. When the PP and the PE-PP of thepolymer resin 71 is in the ratio, the PP may be effectively preventedfrom crystallizing and may have high mechanical strength, thuseffectively improving the haze characteristics. In one exemplaryembodiment, for example, the polymer resin 71 may include the PP and thePE-PP in a weight ratio in a range from about 4:6 to about 6:4, or in arange from about 5:5.

The polymer resin 71 may have a MFI in a range from about 1 g/10 min toabout 15 g/10 min. When the polymer resin 71 has a MFI within the range,the polymer resin may not only secure excellent light transmittancesince crystals are not excessively formed in the resin, but may alsohave appropriate viscosity for manufacturing a film, thereby improvingworkability. In one exemplary embodiment, for example, the polymer resin71 may have a MFI in a range from about 5 g/10 min to about 15 g/10 min.

The polymer resin 71 may have haze less than or equal to about 5%. Whenthe polymer resin 71 has haze within the range, transmittance may beincreased, and thus high optical properties may be secured. In oneexemplary embodiment, for example, the polymer resin 71 may have hazeless than or equal to about 2%, or in a range about 0.5% to about 2%.

The polymer resin 71 may have crystallinity less than or equal to about50%. When the polymer resin 71 has crystallinity within the range, thepolymer resin may have lower haze and accomplish excellent opticalproperties. In one exemplary embodiment, for example, the polymer resin71 may have crystallinity in a range from about 30% to about 50%.

The polymer resin 71 may have transmittance greater than or equal toabout 85% in a wavelength region of about 400 nanometers (nm) to about780 nm. The polymer resin 71 may be elongated in a uniaxial direction.The direction may be the length direction of the dichroic dye 72.

In an exemplary embodiment, the dichroic dye 72 is dispersed into thepolymer resin 71 and aligned in the elongation direction of the polymerresin 71. The dichroic dye 72 transmits a polarization component of twopolarization components perpendicular to each other in a predeterminedwavelength region.

The dichroic dye 72 may be included in an amount in a range from about0.01 parts by weight to about 5 parts by weight, based on 100 parts byweight of the polymer resin 71. When the dichroic dye 72 is within therange, sufficient polarization characteristics may be obtained withoutdeteriorating transmittance of a polarization film. In one exemplaryembodiment, for example, the dichroic dye 72 may be included in anamount of about 0.05 part by weight to about 1 part by weight, based on100 parts by weight of the polymer resin 71.

The polarization film 110 may have a dichroic ratio in a range fromabout 2 to about 14 at a maximum absorption wavelength (λ_(max)) in avisible ray region. In one exemplary embodiment, for example, thedichroic ratio may be in a range from about 3 to about 10. Herein, thedichroic ratio is a value obtained by dividing linear polarizationabsorption in a direction perpendicular to the axis of the polymer bypolarization absorption in a direction parallel to the polymer, and thedichroic ratio of a polarization film may be obtained by the followingEquation 1.DR=Log(1/T _(⊥))/Log(1/T _(∥))  Equation 1:

In the Equation 1, DR denotes the dichroic ratio of the polarizationfilm, T_(∥) denotes light transmittance of light entering parallel tothe transmissive axis of the polarization film, and T_(⊥) denotes lighttransmittance of light entering perpendicular to the transmissive axisof the polarization film.

The dichroic ratio refers to a degree that the dichroic dye 72 isaligned in one direction in the polarization film 110. The polarizationfilm 110 has a dichroic ratio within the range in a visible raywavelength region, by allowing the dichroic dye 72 to be aligned alongthe alignment of a polymer chain, and thus the polarizing characteristicthereof may be improved.

The polarization film 110 may have polarizing efficiency greater than orequal to about 80%, e.g., in a range from about 83% to about 99.9%.Herein, the polarizing efficiency of a polarization film may be obtainedby the following Equation 2.PE (%)=[(T _(∥) −T _(⊥))/(T _(∥) +T _(⊥))]^(1/2)□100  Equation 2:

In the Equation 2, PE denotes the polarizing efficiency, T_(∥) denoteslight transmittance of the polarization film regarding light parallel tothe transmissive axis of the polarization film, and T_(⊥) denotes lighttransmittance of the polarization film regarding light perpendicular tothe transmissive axis of the polarization film.

The polarizing film 110 may have a relatively thin thickness less thanor equal to about 100 micrometers (μm), for example, in a range fromabout 30 μm to about 95 μm. When the polarizing film 70 has a thicknesswith the range, the polarizing film 70 may be thinner than a polarizingplate including a protective layer such as triacetyl cellulose (“TAC”),such that a display device including the polarizing film 70 may have areduced thickness.

The phase delay layer 120 may be disposed on the polarization film 110,and may include an anisotropic liquid crystal layer including liquidcrystal.

The liquid crystal may have a rigid-rod shape that is aligned in a samedirection or a flat-disc shape, and may be, for example a monomer, anoligomer, or a polymer. The liquid crystal may have, for example,positive or negative birefringence. The birefringence (Δn) is adifference acquired by subtracting the refractive index (n₀) of lightpropagating perpendicular to an optical axis from the refractive index(n_(e)) of light propagating parallel to the optical axis. The liquidcrystal may be aligned in a predetermined direction along the opticalaxis.

The liquid crystal may be a reactive mesogen liquid crystal, and mayhave, for example, a reactive cross-linking group. The reactive mesogenliquid crystal may include, for example, a rod-shaped aromaticderivative having at least one reactive cross-linking group, propyleneglycol 1-methyl, propylene glycol 2-acetate, a compound represented byP1-A1-(Z1-A2)n-P2, or a combination thereof, where P1 and P2independently include acrylate, methacrylate, vinyl, vinyloxy, epoxy ora combination thereof, A1 and A2 independently include a 1,4-phenylene,naphthalene-2,6-diyl group or a combination thereof, Z1 includes asingle bond, —COO—, —OCO— or a combination thereof, and n is 0, 1 or 2,but is not limited thereto.

The phase delay layer 120 may have inverse wavelength dispersion phasedelay. Herein, the inverse wavelength dispersion phase delay means thatretardation of light having a long wavelength is higher than retardationof light having a short wavelength.

The phase delay may be represented by in-plane phase retardation(R_(e0)), and in-plane phase retardation (R_(e0)) may be represented bythe following equation: R_(e0)=(n_(x0)-n_(y0))×d₀. Herein, n_(x0)denotes a refractive index in a direction having a highest refractiveindex in a plane of the phase delay layer 120 (hereinafter referred toas “slow axis”), n_(y0) denotes a refractive index in a direction havinga lowest refractive index in a plane of the phase delay layer 120(hereinafter referred to as “fast axis”), and d₀ denotes a thickness ofthe phase delay layer 120.

The in-plane phase retardation may be provided within a predeterminedrange by changing thicknesses or refractive indices at the slow or fastaxis of the phase delay layer 120.

According to one exemplary embodiment, the in-plane phase retardation(R_(e0)) of the phase delay layer 120 for 550 nm wavelength (hereinafterreferred to as “reference wavelength”) may be in a range from about 120nm to about 160 nm.

In the phase delay layer 120, the retardation of light having a longwavelength is higher than the retardation of light having a shortwavelength as described above. In one exemplary embodiment, for example,the in-plane phase retardation (R_(e0)) of the phase delay layer 120 for450 nm, 550 nm, and 650 nm wavelengths may satisfy the followinginequality: R_(e0) (450 nm)≤R_(e0) (550 nm)<R_(e0) (650 nm) or R_(e0)(450 nm)<R_(e0) (550 nm)≤R_(e0) (650 nm). Herein, R_(e0) (450 nm)denotes the in-plane phase retardation for 450 nm wavelength, R_(e0)(550 nm) denotes in-plane phase retardation for 550 nm wavelength, andR_(e0) (650 nm) denotes in-plane phase retardation for 650 nmwavelength.

The changing of the retardation of the short wavelength for thereference wavelength may be represented by short wavelength dispersion,that is, R_(e0) (450 nm)/R_(e0) (550 nm). In one exemplary embodiment,for example, the short wavelength dispersion of the phase delay layer120 may be in a range from about 0.70 to about 0.99.

The changing of the retardation of the long wavelength for the referencewavelength may be represented by long wavelength dispersion, that is,R_(e0) (650 nm)/R_(e0) (550 nm). In one exemplary embodiment, forexample, the long wavelength dispersion of the phase delay layer 120 maybe in a range from about 1.01 to about 1.20.

On the other hand, the retardation includes thickness directionretardation (R_(th)) besides the in-plane retardation (R_(e0)). Thethickness direction retardation (R_(th0)) is retardation generated in athickness direction of the phase delay layer 120, and the thicknessdirection retardation (R_(th0)) of the phase delay layer 120 may berepresented by the following equation:R_(th0)={[(n_(x0)+n_(y0))/2]−n_(z0)}×d₀. Herein, n_(x0) denotes arefractive index at a slow axis of the phase delay layer 120, n_(y0)denotes a refractive index at a fast axis of the phase delay layer 120,and n_(z0) denotes a refractive index of the phase delay layer 120 in adirection perpendicular to the fast and slow axes thereof.

In one exemplary embodiment, for example, thickness directionretardation (R_(th0)) of the phase delay layer 120 for a referencewavelength may be in a range from about −250 nm to about 250 nm.

The phase delay layer 120 may have a thickness less than or equal toabout 10 μm.

The phase delay layer 120 may be disposed on the polarization film 110,and the phase delay layer 120 and the polarization film 110 may contacteach other directly or an adhesion layer (not shown) may be interposedtherebetween. Herein, the adhesion layer may include, for example, apressure sensitive adhesive.

In one exemplary embodiment, for example, the optical film 100 may beprepared by melt-blending a polymer resin and a dichroic dye to preparea polarization film 110, preparing a phase delay layer 120 includingliquid crystal on a substrate, and forming the phase delay layer 120 ona surface of the polarization film 110.

In an exemplary embodiment, the polarization film 110 is prepared bymelt-blending a composition including the polymer resin 71 and thedichroic dye 72, putting the melt-blend into a mold and pressing it intoa sheet, and elongating the sheet in a uniaxial direction.

In an exemplary embodiment, the polymer resin 71 and the dichroic dye 72may be independently in a solid form such as a powder, and may bemelt-blended at a temperature above the melting point (T_(m)) of thepolymer resin 71 and elongated to prepare the polarization film 110.

The melt-blending may be performed at a temperature less than or equalto about 300° C., or in a range from about 130° C. to about 300° C. Thesheet may be formed by putting the melt blend in the mold, and pressingthe melt blend with a high pressure or discharging the melt blend in achill roll through a T-die. The elongation in a uniaxial direction maybe performed at a temperature in a range from about 25° C. to about 200°C. at an elongation rate in a range from about 400% to about 1000%. Theelongation rate refers to a length ratio of after the elongation tobefore the elongation of the sheet, and represents the elongation extentof the sheet after uniaxial elongation.

The phase delay layer 120 may be prepared by coating a liquid crystalsolution on a substrate and curing the coated liquid crystal solutionwith photo-radiation. The substrate may be, for example, a TAC film, butis not limited thereto. The phase delay layer 120 may be prepared byremoving the phase delay layer 120 from the substrate and transferringthe phase delay layer 120 on a surface of the polarization film 110.Herein, an adhesion layer may be provided, e.g., formed, on a surface ofthe polarization film 110 or on a surface of the phase delay layer 120.However, the transferring method is not limited to the above method, andmay be, for example, roll-to-roll, spin coating, and the like.

The optical film 100 may further include a correction layer (not shown)disposed on the phase delay layer 120. The correction layer may be, forexample, a color shift resistant layer, but is not limited thereto.

The optical film 100 may further include a light blocking layer (notshown) extending along an edge thereof. The light blocking layer mayhave a strip shape extending along a circumference of the optical film100, and for example, may be disposed between the polarization film 110and the phase delay layer 120. The light blocking layer may include anopaque material, for example, a black material. In one exemplaryembodiment, for example, the light blocking layer may include or be madeof a black ink.

Hereinafter, an alternative exemplary embodiment of an optical filmaccording to the invention will be described.

FIG. 4 is a schematic view of an alternative exemplary embodiment of anoptical film according to the invention.

Referring to FIG. 4, the optical film 100 includes a polarization film110 and a phase delay layer 120 disposed on the polarization film 110.

In an exemplary embodiment, as shown in FIG. 4, the phase delay layer120 may include a plurality of phase delay layers, e.g., a first phasedelay layer 120 a and a second phase delay layer 120 b having differentretardation from each other.

In such an embodiment, one of the first phase delay layer 120 a and thesecond phase delay layer 120 b may be a λ/2 phase delay layer 120, andthe other may be a λ/4 phase delay layer 120. In one exemplaryembodiment, for example, the first phase delay layer 120 a may be a λ/2phase delay layer 120 and the second phase delay layer 120 b may be aλ/4 phase delay layer 120.

The first phase delay layer 120 a and the second phase delay layer 120 bmay each be an anisotropic liquid crystal layer including liquidcrystal, and the first phase delay layer 120 a and the second phasedelay layer 120 b may independently have positive or negativebirefringence.

The first phase delay layer 120 a and second phase delay layer 120 b mayeach have forward wavelength dispersion phase delay, and a combinationof the first phase delay layer 120 a and the second phase delay layer120 b may have an inverse wavelength dispersion phase delay. The forwardwavelength dispersion phase delay has higher retardation of light havinga short wavelength than retardation of light having a long wavelength,and the reverse wavelength dispersion phase delay has higher retardationof light having a long wavelength than retardation of light having ashort wavelength.

The phase delay may be represented by in-plane phase retardation,in-plane phase retardation (R_(e1)) of the first phase delay layer 120 amay be represented by the following equation: R_(e1)=(n_(x1)−n_(y1))×d₁,in-plane phase retardation (R_(e2)) of the second phase delay layer 120b may be represented by the following equation:R_(e2)=(n_(x2)−n_(y2))×d₂, and the entire in-plane phase retardation(R_(e0)) of the phase delay layer 120 may be represented by thefollowing equation: R_(e0)=(n_(x0)−n_(y0))×d₀. Herein, n_(x1) denotes arefractive index at a slow axis of the first phase delay layer 120 a,n_(y1) denotes a refractive index at a fast axis of the first phasedelay layer 120 a, d₁ denotes a thickness of the first phase delay layer120 a, n_(x2) denotes a refractive index at a slow axis of the secondphase delay layer 120 b, n_(y2) denotes a refractive index at a fastaxis of the second phase delay layer 120 b, d₂ denotes a thickness ofthe second phase delay layer 120 b, n_(x0) denotes a refractive index ata slow axis of the phase delay layer 120, n_(y0) denotes a refractiveindex at a fast axis of the phase delay layer 120, and d₀ denotes athickness of the phase delay layer 120.

Accordingly, the in-plane retardation (R_(e1) and R_(e2)) may beprovided within a predetermined range by changing refractive indices atthe slow or fast axis or thicknesses of the first phase delay layer 120a and the second phase delay layer 120 b.

According to one exemplary embodiment, in-plane phase retardation(R_(e1)) for a reference wavelength of the first phase delay layer 120 amay be in a range from about 230 nm to about 270 nm, in-plane phaseretardation (R_(e2)) for a reference wavelength of the second phasedelay layer 120 b may be in a range from about 100 nm to about 140 nm,entire in-plane phase retardation of the first phase delay layer 120 aand the second phase delay layer 120 b, that is, in-plane phaseretardation (R_(e0)) of the phase delay layer 120, for incident lighthaving a reference wavelength, may be the difference between thein-plane retardation (R_(e1)) of the first phase delay layer 120 a andthe in-plane retardation (R_(e2)) of the second phase delay layer 120 b.In one exemplary embodiment, for example, the in-plane phase retardation(R_(e0)) of the phase delay layer 120 for a reference wavelength may bein a range from about 120 nm to about 160 nm.

In the first phase delay layer 120 a and the second phase delay layer120 b, the retardation of light having a short wavelength may be higherthan the retardation of light having a long wavelength as describedabove. In one exemplary embodiment, for example, the in-planeretardation (R_(e1)) of the first phase delay layer 120 a for thewavelengths of 450 nm, 550 nm and 650 nm may satisfy the followinginequality: R_(e1) (450 nm)≥R_(e1) (550 nm)>R_(e1) (650 nm) or R_(e1)(450 nm)>R_(e1) (550 nm)≥R_(e1) (650 nm), and the in-plane retardation(R_(e2)) of the second phase delay layer 120 b for the wavelengths of450 nm, 550 nm and 650 nm may satisfy the following inequality: R_(e2)(450 nm)>R_(e2) (550 nm)>R_(e2) (650 nm).

The combination of the first phase delay layer 120 a and the secondphase delay layer 120 b may have higher retardation of light having along wavelength than the retardation of light having a short wavelengthas described above. In one exemplary embodiment, for example, thein-plane phase retardation (R_(e0)) of the first phase delay layer 120 aand the second phase delay layer 120 b at 450 nm, 550 nm and 650 nmwavelengths may satisfy the following inequality: R_(e0) (450 nm)≤R_(e0)(550 nm)<R_(e0) (650 nm) or R_(e0) (450 nm)<R_(e0) (550 nm)≤R_(e0) (650nm).

The changing of the retardation of the short wavelength for thereference wavelength may be represented by short wavelength dispersion,the short wavelength dispersion of the first phase delay layer 120 a maybe represented by R_(e1) (450 nm)/R_(e1) (550 nm), and the shortwavelength dispersion of the second phase delay layer 120 b may berepresented by R_(e2) (450 nm)/R_(e2) (550 nm). In one exemplaryembodiment, for example, the short wavelength dispersion of the firstphase delay layer 120 a and the second phase delay layer 120 b mayindependently be in a range from about 1.1 to about 1.2, and the entireshort wavelength dispersion of the first phase delay layer 120 a and thesecond phase delay layer 120 b may be in a range from about 0.70 toabout 0.99.

The changing of the retardation of the long wavelength for the referencewavelength may be represented by long wavelength dispersion, the longwavelength dispersion of the first phase delay layer 120 a may berepresented by R_(e1) (650 nm)/R_(e1) (550 nm), and the long wavelengthdispersion of the second phase delay layer 120 b may be represented byR_(e2) (650 nm)/R_(e2) (550 nm). In one exemplary embodiment, forexample, the long wavelength dispersion of the first phase delay layer120 a and the second phase delay layer 120 b may independently be in arange from about 0.9 to about 1.0, and the entire long wavelengthdispersion of the first phase delay layer 120 a and the second phasedelay layer 120 b may be in a range from about 1.01 to about 1.20.

On the other hand, the thickness direction retardation (R_(th1)) of thefirst phase delay layer 120 a may be represented by the followingequation: R_(th1)={[(n_(x1)+n_(y1))/2]−n_(z1)}×d₁, the thicknessdirection retardation (R_(th2)) of the second phase delay layer 120 bmay be represented by the following equation:R_(th2)={[(n_(x2)+n_(y2))/2]−n_(z2)}×d₂, and the thickness directionretardation (R_(th0)) of the combined first phase delay layer 120 a andthe second phase delay layer 120 b may be represented by the followingequation: R_(th0)={[(n_(x0)+n_(y0))/2]−n_(z0)}×d₀. Herein, n_(x1)denotes a refractive index at a slow axis of the first phase delay layer120 a, n_(y1) denotes a refractive index at a fast axis of the firstphase delay layer 120 a, n_(z1) denotes a refractive index of the firstphase delay layer 120 a in a direction perpendicular to the slow andfast axes thereof, n_(x2) denotes a refractive index at a slow axis ofthe second phase delay layer 120 b, n_(y2) denotes a refractive index ata fast axis of the second phase delay layer 120 b, n_(z2) denotes arefractive index of the second phase delay layer 120 b in a directionperpendicular to the fast and slow axes thereof, n_(x0) denotes arefractive index at a slow axis of the phase delay layer 120, n_(y0)denotes a refractive index at a fast axis of the phase delay layer 120,and n_(z0) denotes a refractive index of the phase delay layer 120 in adirection perpendicular to the fast and slow axes thereof.

The thickness direction retardation (R_(th0)) of the phase delay layer120 may be the sum of the thickness direction retardation (R_(th1)) ofthe first phase delay layer 120 a and the thickness directionretardation (R_(th2)) of the second phase delay layer 120 b.

An angle between a slow axis of the first phase delay layer 120 a and aslow axis of the second phase delay layer 120 b may be in a range fromabout 50 to about 70 degrees. In one exemplary embodiment, for example,the angle may be, for example, in a range from about 55 to about 65degrees, in a range from about 52.5 to about 62.5 degrees, or in a rangefrom about 60 degrees. In one exemplary embodiment, for example, theslow axis of the first phase delay layer 120 a may be about 15 degrees,the slow axis of the second phase delay layer 120 b may be about 75degrees, and an angle therebetween may be about 60 degrees.

In an exemplary embodiment, the first phase delay layer 120 a and thesecond phase delay layer 120 b may independently have respectiverefractive indices satisfying the following relationship 1A or 1B.n _(x) >n _(y) =n _(z)  Relationship Equation 1A:n _(x) <n _(y) =n _(z)  Relationship Equation 1B:

In the Relationship Equation 1A and 1B, n_(x) denotes a refractive indexof the first or second phase delay layer at a slow axis thereof, n_(y)denotes a refractive index of the first or second phase delay layer at afast axis thereof, and n_(z) denotes a refractive index of the first orsecond phase delay layer in a direction perpendicular to the fast andslow axes thereof.

As an example, the first phase delay layer 120 a and the second phasedelay layer 120 b may have refractive indices satisfying therelationship 1A, respectively.

As an example, the first phase delay layer 120 a and the second phasedelay layer 120 b may have refractive indices satisfying therelationship 1B, respectively.

As an example, the first phase delay layer 120 a may have refractiveindices satisfying the relationship 1A and the second phase delay layer120 b may have refractive indices satisfying the relationship 1B.

As an example, the first phase delay layer 120 a may have refractiveindices satisfying the relationship 1B and the second phase delay layer120 b may have refractive indices satisfying the relationship 1A.

The first phase delay layer 120 a and the second phase delay layer 120 bmay independently be less than or equal to about 5 μm.

In an exemplary embodiment, the first phase delay layer 120 a and thesecond phase delay layer 120 b may contact directly each other. In analternative exemplary embodiment, an adhesion layer (not shown) may bedisposed therebetween. In such an embodiment, the adhesion layer mayinclude, for example, a pressure sensitive adhesive.

In an exemplary embodiment, the first phase delay layer 120 a and thesecond phase delay layer 120 b may be formed by applying a liquidcrystal solution on a substrate. In such an embodiment, the first phasedelay layer 120 a and the second phase delay layer 120 b may be formedon respective substrates or be sequentially formed on a same substrate.The substrate may be, for example, a TAC film, but is not limitedthereto. The solution may include a liquid crystal and a solvent such astoluene, xylene, cyclohexanone, and the like, and the solution may be,for example, applied on the transparent substrate with a solutionprocess such as spin coating. Subsequently, the solution may be furtherdried, and for example, cured with ultraviolet (“UV”) rays.

The phase delay layer 120 may accomplish the reverse wavelengthdispersion delay by assembling the first phase delay layer 120 a and thesecond phase delay layer 120 b having predetermined optical properties,and may provide λ/4 retardation in the entire visible ray region.Accordingly, the phase delay layer 120 may effectively accomplish thecircularly polarized compensation function, and the displaycharacteristics of the display device including an optical filmincluding the polarization film 110 may be improved.

Such an embodiment of the optical film 100 may be applied to variousdisplay devices.

In an exemplary embodiment, a display device includes a display paneland an optical film positioned on a surface of the display panel. Thedisplay panel may be a liquid crystal panel or organic light emittingdiode panel, but is not limited thereto.

Hereinafter, an exemplary embodiment of a display device, where thedisplay device is an organic light emitting display, will be describedin detail.

FIG. 5 is a cross-sectional view showing an exemplary embodiment of anorganic light emitting display according to the invention.

Referring to FIG. 5, an exemplary embodiment of the organic lightemitting display according to the invention includes an organic lightemitting diode panel 400 and an optical film 100 disposed on a surface(e.g., an upper surface or a front surface) of the organic lightemitting diode panel 400.

The organic light emitting diode panel 400 may include a base substrate410, a lower electrode 420, an organic emission layer 430, an upperelectrode 440, and an encapsulation substrate 450.

The base substrate 410 may include or be made of glass or plastic.

At least one of the lower electrode 420 and the upper electrode 440 maybe an anode, and the other one may be a cathode. The anode is anelectrode injected with holes, and may include or be made of atransparent conductive material having a high work function to transmitthe emitted light to the outside, for example, indium tin oxide (“ITO”)or indium zinc oxide (“IZO”). The cathode is an electrode injected withelectrons, and may include be made of a conductive material having a lowwork function and not affecting the organic material, for example,aluminum (Al), calcium (Ca), barium (Ba) or a combination thereof.

The organic emission layer 430 includes an organic material which mayemit light when a voltage is applied to the lower electrode 420 and theupper electrode 440.

In such an embodiment, an auxiliary layer (not shown) may be furtherprovided between the lower electrode 420 and the organic emission layer430 and between the upper electrode 440 and the organic emission layer430. The auxiliary layer balances electrons and holes, and may include ahole transport layer, a hole injection layer (“HIL”), an electroninjection layer (“EIL”), and an electron transporting layer.

The encapsulation substrate 450 may include or be made of glass, metalor a polymer, and may seal the lower electrode 420, the organic emissionlayer 430 and the upper electrode 440, to effectively prevent moistureand/or oxygen inflow from the outside.

The optical film 100 may be disposed on a light-emitting side of theorganic light emitting diode panel 400. In an exemplary embodiment ofthe organic light emitting display having a bottom emission structure,in which light is emitted at a side of the base substrate 410, theoptical film 100 may be disposed on an exterior side of the basesubstrate 410. In an exemplary embodiment of the organic light emittingdisplay having a top emission structure, in which light is emitted at aside of the encapsulation substrate 450, the optical film 100 may bedisposed on an exterior side of the encapsulation substrate 450.

The optical film 100 includes the polarization film 110 and the phasedelay layer 120. In such an embodiment, as described above, thepolarization film 110 may be self-integrated and formed of a melt blendof a polymer resin and a dichroic dye, and the phase delay layer 120 maybe a single-layered or multi-layered (e.g., two-layered) liquid crystalanisotropic layer, as described above. The polarization film 110 and thephase delay layer 120 are substantially the same as those describedabove, and may effectively prevent a display device from havingvisibility deterioration caused by light inflowing from the outsideafter passing the polarization film 110 and being reflected by a metal,such as an electrode and the like, in the organic light emitting diodepanel 400. Accordingly, display characteristics of the organic lightemitting display including such an optical film may be substantiallyimproved.

Hereinafter, a liquid crystal display (“LCD”) is described as oneexample of the display device.

FIG. 6 is a cross-sectional view schematically showing an exemplaryembodiment of an LCD according to the invention.

Referring to FIG. 6, an exemplary embodiment of the LCD according to theinvention includes a liquid crystal panel 500, and an optical film 100disposed on the liquid crystal panel 500. In one exemplary embodiment,for example, the optical film 100 may be disposed on an upper or lowersurface of the liquid crystal panel 500.

The liquid crystal panel 500 may be a twist nematic (“TN”) mode panel, avertical alignment (“PVA”) mode panel, an in-plane switching (“IPS”)mode panel or an optically compensated bend (“OCB”) mode panel, forexample.

In an exemplary embodiment, as shown in FIG. 6, the liquid crystal panel500 may include a first display panel 510, a second display panel 520,and a liquid crystal layer 530 interposed between the first displaypanel 510 and the second display panel 520.

In an exemplary embodiment, the first display panel 510 may include, forexample, a thin film transistor (not shown) disposed on a substrate (notshown) and a first electric field generating electrode (not shown)connected to the thin film transistor, and the second display panel 520may include, for example, a color filter (not shown) disposed on asubstrate (not shown) and a second electric field generating electrode(not shown), but not being limited thereto. In an alternative exemplaryembodiment, the color filter may be included in the first display panel510, and the first electric field generating electrode and the secondelectric field generating electrode may be disposed on the first displaypanel 510.

The liquid crystal layer 530 may include a plurality of liquid crystalmolecules. The liquid crystal molecules may have positive or negativedielectric anisotropy. In an exemplary embodiment, where the liquidcrystal molecules having positive dielectric anisotropy, the major(e.g., longitudinal) axes thereof may be aligned substantially parallelto the surface of the first display panel 510 and the second displaypanel 520 when an electric field is not applied thereto, and the majoraxes may be aligned substantially perpendicular to the surface of thefirst display panel 510 and second display panel 520 when an electricfield is applied thereto. In an exemplary embodiment, where the liquidcrystal molecules having negative dielectric anisotropy, the major axesmay be aligned substantially perpendicular to the surface of the firstdisplay panel 510 and the second display panel 520 when an electricfield is not applied thereto, and the major axes may be alignedsubstantially parallel to the surface of the first display panel 510 andthe second display panel 520 when an electric field is applied thereto.

In an exemplary embodiment, the optical film 100 may be disposed on theoutside (e.g., an external surface) of the liquid crystal panel 500. Inan exemplary embodiment, as shown in FIG. 6, the optical film 100 may bedisposed on both opposing surfaces (e.g., lower and upper surfaces) ofthe liquid crystal panel 500, but not being limited thereto. In analternative exemplary embodiment, the optical film 100 may be disposedon only one of the lower and upper surfaces of the liquid crystal panel500.

The optical film 100 include the polarization film 110, which may beself-integrated and formed of a melt blend of a polymer resin and adichroic dye, and the phase delay layer 120, which is a one- ortwo-layered liquid crystal anisotropic layer as described above. In suchan embodiment, the optical film 100 is substantially the same as theoptical film described above, and any repetitive detailed descriptionthereof will be omitted.

Hereinafter, the disclosure will be described in greater detail withreference to examples. However, these examples are described forexemplary purposes only, and the invention is not limited thereto orthereby.

Manufacture of Polarization Film or Polarizing Plate Preparation Example1

A composition for a polarization film is prepared by mixing a polymerresin including PP and a PP-PE in a weight ratio of 5:5 (w/w), and eachdichroic dye represented by the following Chemical Formulae A, B and Cin amounts of 0.5, 0.2 and 0.3 parts by weight, respectively, based on100 parts by weight of the polymer resin.

The composition for a polarization film is melt-mixed at 250° C. using aMicro-compounder made by DSM. The melt blend is put in a sheet-shapedmold and pressed with a high pressure at a high temperature, therebymanufacturing a film. Subsequently, the film is 1000% elongated in auniaxial direction at 115° C. (using a tensile tester made by Instron),thereby manufacturing a 20 μm-thick polarization film.

Comparative Preparation Example 1

A polyvinyl alcohol (“PVA”) film (PS 60, Kuraray) is elongated, therebymanufacturing a 30 μm-thick PVA film. Subsequently, a 40 μm-thick TACfilm (Fuji Film Corp.) is respectively attached on both sides of theelongated PVA film, thereby manufacturing a polarizing plate.

Preparation of Phase Delay Layer Preparation Example 2

A 60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed to be aligned inone direction, coated with biaxial liquid crystals (n_(x)≠n_(y)≠n_(z),RMS03-0130, Merck & Co., Inc.), and dried in a drying oven at 60° C. for1 minute to remove a coating solvent. Subsequently, the coated liquidcrystals are photo-cross-linked by UV rays at 80 milliwatts per squarecentimeter (mW/cm²) for 30 seconds in a container filled with nitrogen,forming a λ/4 phase delay layer having optical properties as in thefollowing Table 1. Then, in-plane phase retardation, thickness directionretardation, and wavelength dispersion of the λ/4 phase delay layer aremeasured by using Axoscan equipment (Axometrics Inc.).

TABLE 1 In-plane phase Thickness retardation Wavelength dispersiondirection (R_(e)) R_(e) (450 nm)/ R_(e) (650 nm)/ retardation ThicknessR_(e) (550 nm) R_(e) (550 nm) R_(e) (550 nm) (R_(th)) (μm) λ/4 143 0.911.01 106 4

Preparation Example 3

A 60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed to be aligned inone direction, coated with +A plate liquid crystals (n_(x)>n_(y)=n_(z),RMM141C, Merck & Co., Inc.), and dried in an oven at 60° C. for 1 minuteto remove a coating solvent. Subsequently, the coated liquid crystalsare photo-cross-linked by radiating UV rays at 80 mW/cm² for 30 secondsin a container filled with nitrogen, forming a λ/2 phase delay layerhaving optical properties as in the following Table 2. Subsequently, a60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed andorientation-treated in one direction, coated with +A plate liquidcrystals (n_(x)>n_(y)=n_(z), RMM141C, Merck & Co., Inc.), and then driedin an oven at 60° C. for 1 minutes to remove a coating solvent.Subsequently, the coated crystal are photo-cross-linked by radiating UVrays at 80 mW/cm² for 30 seconds in a container filled with nitrogen,forming a λ/4 phase delay layer having optical properties as in thefollowing Table 2.

TABLE 2 In-plane phase Thickness retardation Wavelength dispersiondirection (R_(e)) R_(e) (450 nm)/ R_(e) (650 nm)/ retardation ThicknessR_(e) (550 nm) R_(e) (550 nm) R_(e) (550 nm) (R_(th)) (μm) λ/2 249 1.120.95 116 2 λ/4 122 1.12 0.95 56 1 λ/2 + 140 0.77 1.09 172 3 λ/4

Preparation Example 4

A 60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed to be aligned inone direction, coated with +A plate liquid crystals (n_(x)>n_(y)=n_(z),RMM141C, Merck & Co., Inc.), and dried in an oven at 60° C. for 1 minuteto remove a coating solvent. Subsequently, the coated liquid crystalsare photo-cross-linked by radiating UV rays at 80 mW/cm² for 30 secondsin a container filled with nitrogen, forming a λ/2 phase delay layerhaving optical properties as in the following Table 3. Subsequently, a60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed andorientation-treated in one direction, coated with +A plate liquidcrystals (n_(x)>n_(y)=n_(z), RMM141C, Merck & Co., Inc.), and then driedin an oven at 60° C. for 1 minutes to remove a coating solvent.Subsequently, the coated crystal are photo-cross-linked by radiating UVrays at 80 mW/cm² for 30 seconds in a container filled with nitrogen,forming a λ/4 phase delay layer having optical properties as in thefollowing Table 3.

TABLE 3 In-plane phase Thickness retardation Wavelength dispersiondirection (R_(e)) R_(e) (450 nm)/ R_(e) (650 nm)/ retardation ThicknessR_(e) (550 nm) R_(e) (550 nm) R_(e) (550 nm) (R_(th)) (μm) λ/2 240 1.120.95 110 2 λ/4 120 1.12 0.97 57 1 λ/2 + 134 0.78 1.06 167 3 λ/4

Preparation Example 5

A 60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed to be aligned inone direction, coated with −A plate liquid crystals (n_(x)<n_(y)=n_(z),discotic liquid crystal), and dried in an oven at 60° C. for 1 minute toremove a coating solvent. Subsequently, the coated liquid crystals arephoto-cross-linked by radiating UV rays at 80 mW/cm² for 30 seconds in acontainer filled with nitrogen, forming a λ/2 phase delay layer havingoptical properties as in the following Table 4. Subsequently, a 60μm-thick Z-TAC film (Fuji Film Corp.) is rubbed and orientation-treatedin one direction, coated with −A plate liquid crystals(n_(x)<n_(y)=n_(z), discotic liquid crystal), and then dried in an ovenat 60° C. for 1 minutes to remove a coating solvent. Subsequently, thecoated crystal are photo-cross-linked by radiating UV rays at 80 mW/cm²for 30 seconds in a container filled with nitrogen, forming a λ/4 phasedelay layer having optical properties as in the following Table 4.

TABLE 4 In-plane phase Thickness retardation Wavelength dispersiondirection (R_(e)) R_(e) (450 nm)/ R_(e) (650 nm)/ retardation ThicknessR_(e) (550 nm) R_(e) (550 nm) R_(e) (550 nm) (R_(th)) (μm) λ/2 240 1.090.96 −105 2 λ/4 120 1.08 0.96 −56 1 λ/2 + 141 0.78 1.10 −161 3 λ/4

Preparation Example 6

A 60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed to be aligned inone direction, coated with −A plate liquid crystals (n_(x)<n_(y)=n_(z),discotic liquid crystal), and dried in an oven at 60° C. for 1 minute toremove a coating solvent. Subsequently, the coated liquid crystals arephoto-cross-linked by radiating UV rays at 80 mW/cm² for 30 seconds in acontainer filled with nitrogen, forming a λ/2 phase delay layer havingoptical properties as in the following Table 5. Subsequently, a 60μm-thick Z-TAC film (Fuji Film Corp.) is rubbed and orientation-treatedin one direction, coated with +A plate liquid crystals(n_(x)>n_(y)=n_(z), RMM141C, Merck & Co., Inc.), and then dried in anoven at 60° C. for 1 minutes to remove a coating solvent. Subsequently,the coated crystal are photo-cross-linked by radiating UV rays at 80mW/cm² for 30 seconds in a container filled with nitrogen, forming a λ/4phase delay layer having optical properties as in the following Table 5.

TABLE 5 In-plane phase Thickness retardation Wavelength dispersiondirection (R_(e)) R_(e) (450 nm)/ R_(e) (650 nm)/ retardation ThicknessR_(e) (550 nm) R_(e) (550 nm) R_(e) (550 nm) (R_(th)) (μm) λ/2 240 1.090.96 −105 2 λ/4 120 1.12 0.97 57 1 λ/2 + 138 0.84 1.08 −48 3 λ/4

Preparation Example 7

A 60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed to be aligned inone direction, coated with +A plate liquid crystals (n_(x)>n_(y)=n_(z),RMM141C, Merck & Co., Inc.), and dried in an oven at 60° C. for 1 minuteto remove a coating solvent. Subsequently, the coated liquid crystalsare photo-cross-linked by radiating UV rays at 80 mW/cm² for 30 secondsin a container filled with nitrogen, forming a λ/2 phase delay layerhaving optical properties as in the following Table 6. Subsequently, a60 μm-thick Z-TAC film (Fuji Film Corp.) is rubbed andorientation-treated in one direction, coated with −A plate liquidcrystals (n_(x)<n_(y)=n_(z), discotic liquid crystal), and then dried inan oven at 60° C. for 1 minutes to remove a coating solvent.Subsequently, the coated crystal are photo-cross-linked by radiating UVrays at 80 mW/cm² for 30 seconds in a container filled with nitrogen,forming a λ/4 phase delay layer having optical properties as in thefollowing Table 6.

TABLE 6 In-plane phase Thickness retardation Wavelength dispersiondirection (R_(e)) R_(e) (450 nm)/ R_(e) (650 nm)/ retardation ThicknessR_(e) (550 nm) R_(e) (550 nm) R_(e) (550 nm) (R_(th)) (μm) λ/2 240 1.120.95 110 2 λ/4 120 1.08 0.96 −56 1 λ/2 + 136 0.80 1.08 54 3 λ/4Manufacture of Optical Film

Example 1

An adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is coated ona surface of the polarization film according to Preparation Example 1,and the polarization film is disposed to face the phase delay layeraccording to Preparation Example 2. Subsequently, the phase delay layeris transferred on the adhesive, while the Z-TAC film is removed,manufacturing an optical film. The polarization film has an optical axisof 0°, the phase delay layer has a slow axis of 45°, and the opticalfilm is about 34 μm thick.

Example 2

An adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is coated ona surface of the polarization film according to Preparation Example 1,and then the polarization film is disposed to face the λ/2 phase delaylayer according to Preparation Example 3. The λ/2 phase delay layer istransferred on the adhesive, while the Z-TAC film is removed.Subsequently, an adhesive (PS-47, Soken Chemical & Engineering Co.,Ltd.) is coated on a surface of the λ/2 phase delay layer. The λ/4 phasedelay layer according to Preparation Example 3 is disposed on theadhesive to face the λ/2 phase delay layer, and then the λ/4 phase delaylayer is transferred, while the Z-TAC film is removed, manufacturing anoptical film. The polarization film has an optical axis of 0°, the λ/2phase delay layer has a slow axis of 15°, the λ/4 phase delay layer hasa slow axis of 75°, and the optical film is about 38 μm thick.

Example 3

An adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is coated ona surface of the polarization film according to Preparation Example 1,and then the polarization film is disposed to face the λ/2 phase delaylayer according to Preparation Example 4. The λ/2 phase delay layer istransferred on the adhesive, while the Z-TAC film is removed.Subsequently, an adhesive (PS-47, Soken Chemical & Engineering Co.,Ltd.) is coated on a surface of the λ/2 phase delay layer. The λ/4 phasedelay layer according to Preparation Example 3 is disposed on theadhesive to face the λ/2 phase delay layer, and then the λ/4 phase delaylayer is transferred, while the Z-TAC film is removed, manufacturing anoptical film. The polarization film has an optical axis of 0°, the λ/2phase delay layer has a slow axis of 15°, the λ/4 phase delay layer hasa slow axis of 75°, and the optical film is about 38 μm thick.

Example 4

An adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is coated ona surface of the polarization film according to Preparation Example 1,and then the polarization film is disposed to face the λ/2 phase delaylayer according to Preparation Example 5. The λ/2 phase delay layer istransferred on the adhesive, while the Z-TAC film is removed.Subsequently, an adhesive (PS-47, Soken Chemical & Engineering Co.,Ltd.) is coated on a surface of the λ/2 phase delay layer. The λ/4 phasedelay layer according to Preparation Example 3 is disposed on theadhesive to face the λ/2 phase delay layer, and then the λ/4 phase delaylayer is transferred, while the Z-TAC film is removed, manufacturing anoptical film. The polarization film has an optical axis of 0°, the λ/2phase delay layer has a slow axis of 15°, the λ/4 phase delay layer hasa slow axis of 75°, and the optical film is about 38 μm thick.

Example 5

An adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is coated ona surface of the polarization film according to Preparation Example 1,and then the polarization film is disposed to face the λ/2 phase delaylayer according to Preparation Example 6. The λ/2 phase delay layer istransferred on the adhesive, while the Z-TAC film is removed.Subsequently, an adhesive (PS-47, Soken Chemical & Engineering Co.,Ltd.) is coated on a surface of the λ/2 phase delay layer. The λ/4 phasedelay layer according to Preparation Example 3 is disposed on theadhesive to face the λ/2 phase delay layer, and then the λ/4 phase delaylayer is transferred, while the Z-TAC film is removed, manufacturing anoptical film. The polarization film has an optical axis of 0°, the λ/2phase delay layer has a slow axis of 15°, the λ/4 phase delay layer hasa slow axis of 75°, and the optical film is about 38 μm thick.

Example 6

An adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is coated ona surface of the polarization film according to Preparation Example 1,and then the polarization film is disposed to face the λ/2 phase delaylayer according to Preparation Example 7. The λ/2 phase delay layer istransferred on the adhesive, while the Z-TAC film is removed.Subsequently, an adhesive (PS-47, Soken Chemical & Engineering Co.,Ltd.) is coated on a surface of the λ/2 phase delay layer. The λ/4 phasedelay layer according to Preparation Example 3 is disposed on theadhesive to face the λ/2 phase delay layer, and then the λ/4 phase delaylayer is transferred, while the Z-TAC film is removed, manufacturing anoptical film. The polarization film has an optical axis of 0°, the λ/2phase delay layer has a slow axis of 15°, the λ/4 phase delay layer hasa slow axis of 75°, and the optical film is about 38 μm thick.

Comparative Example 1

An adhesive (PS-47, Soken Chemical & Engineering Co., Ltd.) is coated ona surface of the polarization film according to Comparative PreparationExample 1, and the polarization film is disposed to face the λ/2 phasedelay layer according to Preparation Example 1. The λ/2 phase delaylayer is transferred, while the Z-TAC film on the adhesive is removed.Subsequently, an adhesive (PS-47, Soken Chemical & Engineering Co.,Ltd.) is coated on a surface of the λ/2 phase delay layer. The λ/4 phasedelay layer according to Preparation Example 3 is disposed on theadhesive to face the λ/2 phase delay layer, and then transferredthereon, while the Z-TAC film is removed, manufacturing an optical film.The polarization film has an optical axis of 0°, the λ/2 phase delaylayer has a slow axis of 15°, the λ/4 phase delay layer has a slow axisof 75°, and the optical film is about 115 μm thick.

Comparative Example 2

A λ/4 phase delay layer having a 50 μm-thick inverse wavelengthdispersion and optical properties as in the following Table 7 (WRS,Teijin Ltd.) is prepared.

Then, an optical film is manufactured by coating an adhesive (PS-47,Soken Chemical & Engineering Co., Ltd.) on a surface of the polarizationfilm according to Preparation Example 1, and uniting the λ/4 phase delaylayer with the polarization film. The polarizing plate has an opticalaxis of 0°, the λ/4 phase delay layer has a slow axis of 45°, and theoptical film is about 80 μm thick.

TABLE 7 In-plane phase Thickness retardation Wavelength dispersiondirection (R_(e)) R_(e) (450 nm)/ R_(e) (650 nm)/ retardation ThicknessR_(e) (550 nm) R_(e) (550 nm) R_(e) (550 nm) (R_(th)) (μm) λ/4 146 0.891.03 73 50Manufacture of Organic Light Emitting Display

Example 7

An organic light emitting display is manufactured by attaching theoptical film according to Example 1 on an organic light emitting diodepanel (Galaxy S4 panel, Samsung Display).

Example 8

An organic light emitting display is manufactured by attaching theoptical film according to Example 2 on an organic light emitting diodepanel (Galaxy S4 panel, Samsung Display).

Example 9

An organic light emitting display is manufactured by attaching theoptical film according to Example 3 on an organic light emitting diodepanel (Galaxy S4 panel, Samsung Display).

Example 10

An organic light emitting display is manufactured by attaching theoptical film according to Example 4 on an organic light emitting diodepanel (Galaxy S4 panel, Samsung Display).

Example 11

An organic light emitting display is manufactured by attaching theoptical film according to Example 5 on an organic light emitting diodepanel (Galaxy S4 panel, Samsung Display).

Example 12

An organic light emitting display is manufactured by attaching theoptical film according to Example 6 on an organic light emitting diodepanel (Galaxy S4 panel, Samsung Display).

Comparative Example 3

An organic light emitting display is manufactured by attaching theoptical film according to Comparative Example 1 on an organic lightemitting diode panel (Galaxy S4 panel, Samsung Display).

Comparative Example 4

An organic light emitting display is manufactured by attaching theoptical film according to Comparative Example 2 on an organic lightemitting diode panel (Galaxy S4 panel, Samsung Display).

Evaluation 1

Reflectance at front of the organic light emitting displays according toExamples 7 and 8 and Comparative Examples 3 and 4 is evaluated.

The reflectance at front is evaluated with a spectrum colorimeter(CM-3600d, Konica Minolta Inc.) by supplying light with a D65 lightsource under reflection of 8° and light-receiving of 2°.

The results are shown in Table 8.

TABLE 8 Comparative Comparative Example 7 Example 8 Example 3 Example 4Reflectance (%) 5.2 5.1 5.0 5.2

Referring to Table 8, the organic light emitting displays according toExamples 7 and 8 showed equivalent reflectance at front to that of theorganic light emitting displays according to Comparative Examples 3 and4. Accordingly, the organic light emitting displays according toExamples 7 and 8 have a thin film shape but no influence on displaycharacteristics by remarkably decreasing thickness of an optical filmwhile showing equivalent reflectance at front.

Evaluation 2

Reflectance and reflective color at front of the organic light emittingdisplays according to Examples 8 to 12 and Comparative Example 4 areevaluated.

The reflectance and the reflective color at front are evaluated with aspectrum colorimeter (DMS, Display Measurement Systems, InstrumentSystems) by supplying light with a D65 light source under reflection of8°.

The reflective color may be represented using CIE-Lab color coordinates.The positive value a* denotes red, the negative value a* denotes green,the positive value b* denotes yellow, and the negative value b* denotesblue. In the CIE-Lab color coordinates, the larger the absolute valuesof a* and b* are, the stronger the colors corresponding thereto are.

The results are shown in Table 9.

TABLE 9 Front reflectance(%) a* b* Δ a*b* Example 8 0.7 −0.9 −6.2 6.3Example 9 0.7 −0.4 −4.2 4.3 Example 10 0.6 −1.3 −5.1 5.3 Example 11 0.60.7 −5.1 5.2 Example 12 0.6 0.1 −4.1 4.1 Comparative 0.7 −1.4 −9.0 9.1Example 4 Δ a * b * = {square root over (a *²  + b *²)}

Referring to Table 9, the organic light emitting displays according toExamples 8 to 12 showed equivalent or improved reflectance at front andsmaller reflective color values at front than that of the organic lightemitting displays according to Comparative Example 4. The smallerreflective color value means that a color sense by reflection may becloser to black and a change of a color sense may be small and avisibility by reflection due to an external light may be improved. Forexample, the organic light emitting displays according to Examples 8 to12 may have reflective color values at front satisfying 0≤Δa*b*≤9.

Accordingly, the organic light emitting displays according to Examples 8to 12 have a thin film shape but improved display characteristics byremarkably decreasing thickness of an optical film while showingequivalent or improved reflectance and improved reflective color atfront.

Evaluation 3

Reflectance and reflective color at side of the organic light emittingdisplays according to Examples 8 to 12 and Comparative Example 4 areevaluated.

The reflectance and the reflective color at side are evaluated with aspectrum colorimeter (DMS, Display Measurement Systems, InstrumentSystems) by supplying light with a D65 light source under reflection of45°.

The results are shown in Table 10.

TABLE 10 Side reflectance(%) a* b* Δ a*b* Example 8 1.3 −3.2 −0.5 3.3Example 9 1.3 −3.5 0.9 4.0 Example 10 0.8 −1.2 −3.2 3.6 Example 11 1.0−1.1 −1.4 2.0 Example 12 0.8 −0.6 −0.9 1.5 Comparative 1.2 −3.3 −3.3 5.5Example 4 Δ a * b * = {square root over (a *²  + b *²)}

Referring to Table 10, the organic light emitting displays according toExamples 8 to 12 showed equivalent or improved reflectance at side andsmaller reflective color values at side than that of the organic lightemitting displays according to Comparative Example 4. For example, theorganic light emitting displays according to Examples 8 to 12 may havereflective color values at side satisfying 0≤Δa*b*≤5.

Further, it is confirmed that the organic light emitting displaysaccording to Examples 8 to 12 showed a color sense closer to black thanthat of the organic light emitting displays according to ComparativeExample 4.

Accordingly, the organic light emitting displays according to Examples 8to 12 have a thin film shape but improved display characteristics byremarkably decreasing thickness of an optical film while showingequivalent or improved reflectance and improved reflective color atside.

Evaluation 4

Optical durability of the organic light emitting displays according toExample 8 and Comparative Example 3 is evaluated.

The optical durability evaluation includes a thermal stabilityevaluation and a high temperature/high humidity evaluation, and herein,the thermal stability evaluation is performed by allowing the organiclight emitting displays according to Example 8 and Comparative Example 3to stand at 85° C. for 500 hours and measuring their light transmittanceand variations of their degrees of polarization, and the hightemperature/high humidity evaluation is performed by allowing theorganic light emitting displays according to Example 8 and ComparativeExample 3 to stand at 60° C. under humidity of 95% for 500 hours andmeasuring their light transmittance and variations of their degrees ofpolarization.

The results are shown in Table 11.

TABLE 11 Evaluation at Evaluation of high temperature thermal stabilityand high humidity at 85° C. and 500 h (60° C., 95%, 500 h) VariationsVariations Variations Variations of light of degree of of light ofdegree of transmittance polarization transmittance polarization (%) (%)(%) (%) Example 8 0.36 0.37 0.42 0.09 Comparative 0.9 3 6 20 Example 3

Referring to Table 11, the organic light emitting display according toExample 8 shows excellent thermal stability and excellent opticaldurability in a high temperature/high humidity environment.

While the invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. An optical film comprising: a polarization film;and a phase delay layer disposed on the polarization film, wherein thephase delay layer comprises a first phase delay layer and a second phasedelay layer, each of the first and second phase delay layers includingliquid crystal, in-plane phase retardation (R_(e1)) of the first phasedelay layer for 550 nm wavelength is in a range from about 230 nm toabout 270 nm, in-plane phase retardation (R_(e2)) of the second phasedelay layer for 550 nm wavelength is in a range from about 100 nm toabout 140 nm, entire in-plane phase retardation (R_(e0)) of the firstphase delay layer and the second phase delay layer for 550 nm wavelengthis in a range from about 120 nm to about 160 nm, each of the first phasedelay layer and the second phase delay layer has a refractive indexsatisfying the following relationship: n_(x)>n_(y)=n_(z) orn_(x)<n_(y)=n_(z), wherein each of the first phase delay layer and thesecond phase delay layer has a refractive index satisfying the followingrelationship: n_(x)<n_(y)=n_(z), wherein n_(x) denotes a refractiveindex of the first or second phase delay layer at a slow axis thereof,n_(y) denotes a refractive index of the first or second phase delaylayer at a fast axis thereof, and n_(z) denotes a refractive index ofthe first or second phase delay layer in a direction perpendicular tothe fast and slow axes thereof.
 2. The optical film of claim 1, whereinentire in-plane phase retardation (R_(e0)) of the first phase delaylayer and the second phase delay layer for 450 nm, 550 nm, and 650 nmwavelengths satisfies the following inequality: R_(e0) (450 nm)≤R_(e0)(550 nm)<R_(e0) (650 nm) or R_(e0) (450 nm)<R_(e0) (550 nm)≤R_(e0) (650nm).
 3. The optical film of claim 2, wherein the first phase delay layerand the second phase delay layer have entire short wavelength dispersionin a range from about 0.70 to about 0.99, and the first phase delaylayer and the second phase delay layer have entire long wavelengthdispersion in a range from about 1.01 to about 1.20.
 4. The optical filmof claim 1, wherein entire in-plane phase retardation (R_(e0)) of thefirst phase delay layer and the second phase delay layer for 550 nmwavelength is in a range from about 120 nm to about 160 nm.
 5. Theoptical film of claim 1, wherein the first phase delay layer is a λ/2phase delay layer, and the second phase delay layer is a λ/4 phase delaylayer.
 6. The optical film of claim 1, wherein in-plane phaseretardation (R_(e1)) of the first phase delay layer for 450 nm, 550 nmand 650 nm wavelengths satisfies the following inequality: R_(e1) (450nm)>R_(e1) (550 nm)>R_(e1) (650 nm), in-plane phase retardation (R_(e2))of the second phase delay layer for 450 nm, 550 nm and 650 nmwavelengths satisfies the following inequality: R_(e2) (450 nm)>R_(e2)(550 nm)>R_(e2) (650 nm), and entire in-plane phase retardation (R_(e0))of the first phase delay layer and the second phase delay layer for 450nm, 550 nm and 650 nm wavelengths satisfies the following inequality:R_(e0) (450 nm)≤R_(e0) (550 nm)<R_(e0) (650 nm) or R_(e0) (450nm)<R_(e0) (550 nm)≤R_(e0) (650 nm).
 7. The optical film of claim 6,wherein the first phase delay layer and the second phase delay layereach have short wavelength dispersion in a range from about 1.1 to about1.2, and the first phase delay layer and the second phase delay layerhave entire short wavelength dispersion in a range from about 0.70 toabout 0.99.
 8. The optical film of claim 6, wherein the first phasedelay layer and the second phase delay layer each have long wavelengthdispersion in a range from about 0.9 to about 1.0, and the first phasedelay layer and the second phase delay layer have entire long wavelengthdispersion in a range from about 1.01 to about 1.20.
 9. The optical filmof claim 1, wherein an angle between a slow axis of the first phasedelay layer and a slow axis of the second phase delay layer is in arange from about 50 degrees to about 70 degrees.
 10. The optical film ofclaim 1, further comprising: an adhesion layer disposed between thefirst phase delay layer and the second phase delay layer.
 11. Theoptical film of claim 1, wherein the polarization film comprises apolymer resin and a dichroic dye.
 12. The optical film of claim 11,wherein the polymer resin comprises a polyolefin, a polyamide, apolyester, a polyacryl, polystyrene, a copolymer thereof, or acombination thereof.
 13. The optical film of claim 11, wherein thepolarization film comprises a melt blend of the polymer resin and thedichroic dye.
 14. The optical film of claim 1, wherein the polarizationfilm has a thickness less than or equal to about 100 μm and the phasedelay layer has a thickness less than or equal to about 10 μm.
 15. Theoptical film of claim 1, further comprising: an adhesion layer disposedbetween the polarization film and the phase delay layer.
 16. A displaydevice including the optical film of claim
 1. 17. A method ofmanufacturing an optical film, the method comprising: melt-blending apolymer resin and a dichroic dye to prepare a polarization film;preparing a phase delay layer comprising liquid crystal on a substrate;and providing the phase delay layer on the polarization film, whereinthe phase delay layer comprises a first phase delay layer and a secondphase delay layer, each of the first and second phase delay layersincluding liquid crystal, in-plane phase retardation (R_(e1)) of thefirst phase delay layer for 550 nm wavelength is in a range from about230 nm to about 270 nm, in-plane phase retardation (R_(e2)) of thesecond phase delay layer for 550 nm wavelength is in a range from about100 nm to about 140 nm, entire in-plane phase retardation (R_(e0)) ofthe first phase delay layer and the second phase delay layer for 550 nmwavelength is in a range from about 120 nm to about 160 nm, each of thefirst phase delay layer and the second phase delay layer has arefractive index satisfying the following relationship:n_(x)>n_(y)=n_(z) or n_(x)<n_(y)=n_(z), wherein each of the first phasedelay layer and the second phase delay layer has a refractive indexsatisfying the following relationship: n_(x)<n_(y)=n_(z), wherein n_(x)denotes a refractive index of the first or second phase delay layer at aslow axis thereof, n_(y) denotes a refractive index of the first orsecond phase delay layer at a fast axis thereof, and n_(z) denotes arefractive index of the first or second phase delay layer in a directionperpendicular to the fast and slow axes thereof.
 18. The method of claim17, wherein the providing the phase delay layer on the polarization filmcomprises: removing the phase delay layer from the substrate; andtransferring the phase delay layer to a surface of the polarizationfilm.
 19. The method of claim 17, wherein the preparing the phase delaylayer comprises stacking the first phase delay layer and the secondphase delay layer on the substrate, the first phase delay layer being aλ/2 phase delay layer and the second phase delay layer being a λ/4 phasedelay layer.